A sibling spat over the issue of same-sex marriage flared anew as Senate candidate Liz Cheney restated her opposition to gay and lesbian matrimony and her sister — and sister’s spouse — angrily fired back on social media.

The latest installment in the quarrel between the daughters of former Vice President Dick Cheney began when Liz Cheney, who is running in the Republican Senate primary in Wyoming, appeared on “Fox News Sunday.” Referring to her younger sister, Cheney said, "I love Mary very much. I love her family very much. This is just an issue in which we disagree."

Cheney first stated her opposition to same-sex marriage last summer, calling it a matter that "must be decided by the states, and by the people in the states, not by judges and not even by legislators, but by the people themselves."

Mary Cheney, who is gay and married to her longtime partner, Heather Poe, responded: "For the record, I love my sister. But she is dead wrong on the marriage issue."

Cheney and Poe were far more vociferous Sunday after watching the Fox News interview. "Liz – this isn't just an issue on which we disagree you're just wrong – and on the wrong side of history,” said Mary Cheney in a Facebook post.

Poe went further, jabbing at Liz Cheney’s move from the Washington, D.C., suburbs to Wyoming ahead of the Senate race, an issue in her campaign.

“I was watching my sister-in-law on Fox News Sunday (yes Liz, in fifteen states and the District of Columbia you are my sister-in-law) and was very disappointed to hear her say ‘I do believe in the traditional definition of marriage,'" Poe wrote in her post. “Liz has been a guest in our home, has spent time and shared holidays with our children, and when Mary and I got married in 2012 – she didn't hesitate to tell us how happy she was for us.

“To have her now say she doesn't support our right to marry is offensive to say the least. I can't help but wonder how Liz would feel if as she moved from state to state, she discovered that her family was protected in one but not the other. I always thought freedom meant freedom for EVERYONE.”

The issue is likely to have little bearing on the Senate race in Wyoming, where Cheney is waging an uphill fight to unseat three-term Republican incumbent Mike Enzi. The two are both opposed to legalization of same-sex marriage and, in fact, have few substantive differences on most issues.

However, the feuding underscores the unusually personal nature of the contest in a state of fewer than 600,000 residents. The primary has split the state Republican Party and ruptured relationships between some longtime political allies, including the state’s retired U.S. senator, Alan Simpson, and Lynne Cheney, the wife of the former vice president and Wyoming representative and the mother of Liz and Mary.

For his part, the former vice president has endorsed same-sex marriage but stayed publicly silent about the feuding between his daughters.

[Updated, 11:57 a.m. PST Nov. 18: On Monday, the Cheneys issued a statement addressing the feuding between their daughters.

“This is an issue we have dealt with privately for many years, and we are pained to see it become public,” said the couple. “Since it has, one thing should be clear. Liz has always believed in the traditional definition of marriage. She has also always treated her sister and her sister’s family with love and respect, exactly as she should have done. Compassion is called for, even when there is disagreement about such a fundamental matter and Liz’s many kindnesses shouldn’t be used to distort her position.”]